Partial ionic and electronic dc conductivities and compressional creep rate were measured for hot-pressed polycrystalline AlrOs made from Al-isopropoxide (A1203(II)). The undoped material was found to contain 1.5X 1OI8 cm-J fixed valency acceptors (Mg). Properties of undoped material and material doped with Fe or Ti were investigated as a function of grain size, dopant concentration, oxygen pressure, and temperature. No fast ionic conduction along grain boundaries is found in either acceptor-or donor-dominated material. Absolute values of self-diffusion coefficients calculated from conductivity and creep indicate that both effects are limited by migration of Al, involving VAl"' in donor-, Al, ' . ' in acceptor-dominated material.In creep, oxygen is transported along grain boundaries in a neutral form (Oix). The po2 dependence of u, and oh are as expected on the basis of a defect model. That of creep is weaker for reasons that are not entirely clear. An ionic conductivity with low activation energy, observed a t low temperature, is attributed to the presence of AI-silicate second phase.
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